diff --git a/lld/MachO/Arch/ARM64.cpp b/lld/MachO/Arch/ARM64.cpp
--- a/lld/MachO/Arch/ARM64.cpp
+++ b/lld/MachO/Arch/ARM64.cpp
@@ -47,7 +47,6 @@
 
 // Random notes on reloc types:
 // ADDEND always pairs with BRANCH26, PAGE21, or PAGEOFF12
-// SUBTRACTOR always pairs with UNSIGNED (a delta between two sections)
 // POINTER_TO_GOT: ld64 supports a 4-byte pc-relative form as well as an 8-byte
 // absolute version of this relocation. The semantics of the absolute relocation
 // are weird -- it results in the value of the GOT slot being written, instead
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -287,6 +287,10 @@
       p.type = relInfo.r_type;
       p.referent = symbols[relInfo.r_symbolnum];
       relInfo = relInfos[++i];
+      // SUBTRACTOR relocations should always be followed by an UNSIGNED one
+      // indicating the minuend symbol.
+      assert(target->hasAttr(relInfo.r_type, RelocAttrBits::UNSIGNED) &&
+             relInfo.r_extern);
     }
     Reloc r;
     r.type = relInfo.r_type;
@@ -317,8 +321,7 @@
     }
 
     InputSection *subsec = findContainingSubsection(subsecMap, &r.offset);
-    if (p.type != GENERIC_RELOC_INVALID &&
-        target->hasAttr(p.type, RelocAttrBits::SUBTRAHEND))
+    if (p.type != GENERIC_RELOC_INVALID)
       subsec->relocs.push_back(p);
     subsec->relocs.push_back(r);
   }
diff --git a/lld/MachO/InputSection.cpp b/lld/MachO/InputSection.cpp
--- a/lld/MachO/InputSection.cpp
+++ b/lld/MachO/InputSection.cpp
@@ -59,13 +59,13 @@
 
   for (size_t i = 0; i < relocs.size(); i++) {
     auto *fromSym = target->hasAttr(relocs[i].type, RelocAttrBits::SUBTRAHEND)
-                        ? relocs[i++].referent.dyn_cast<Symbol *>()
+                        ? relocs[i++].referent.get<Symbol *>()
                         : nullptr;
     const Reloc &r = relocs[i];
     uint8_t *loc = buf + r.offset;
     uint64_t referentVA = 0;
     if (fromSym) {
-      auto *toSym = r.referent.dyn_cast<Symbol *>();
+      auto *toSym = r.referent.get<Symbol *>();
       referentVA = toSym->getVA() - fromSym->getVA();
     } else if (auto *referentSym = r.referent.dyn_cast<Symbol *>()) {
       if (target->hasAttr(r.type, RelocAttrBits::LOAD) &&
diff --git a/lld/MachO/Target.h b/lld/MachO/Target.h
--- a/lld/MachO/Target.h
+++ b/lld/MachO/Target.h
@@ -52,6 +52,7 @@
   UNSIGNED = 1 << 14,  // *_UNSIGNED relocs
   LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue*/ (1 << 15) - 1),
 };
+// Note: SUBTRACTOR always pairs with UNSIGNED (a delta between two symbols).
 
 class TargetInfo {
 public:
diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -449,9 +449,16 @@
       continue;
     }
 
-    for (Reloc &r : isec->relocs) {
-      if (target->hasAttr(r.type, RelocAttrBits::SUBTRAHEND))
+    for (auto it = isec->relocs.begin(); it != isec->relocs.end(); ++it) {
+      Reloc &r = *it;
+      if (target->hasAttr(r.type, RelocAttrBits::SUBTRAHEND)) {
+        // Skip over the following UNSIGNED relocation -- it's just there as the
+        // minuend, and doesn't have the usual UNSIGNED semantics. We don't want
+        // to emit rebase opcodes for it.
+        it = std::next(it);
+        assert(isa<Defined>(it->referent.dyn_cast<lld::macho::Symbol *>()));
         continue;
+      }
       if (auto *sym = r.referent.dyn_cast<lld::macho::Symbol *>()) {
         if (auto *undefined = dyn_cast<Undefined>(sym))
           treatUndefinedSymbol(*undefined);
diff --git a/lld/test/MachO/reloc-subtractor.s b/lld/test/MachO/reloc-subtractor.s
--- a/lld/test/MachO/reloc-subtractor.s
+++ b/lld/test/MachO/reloc-subtractor.s
@@ -3,9 +3,9 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/x86_64.o
 # RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin %s -o %t/arm64.o
 # RUN: %lld -lSystem %t/x86_64.o -o %t/x86_64
-# RUN: llvm-objdump --syms --full-contents %t/x86_64 | FileCheck %s
+# RUN: llvm-objdump --syms --full-contents --rebase %t/x86_64 | FileCheck %s
 # RUN: %lld -arch arm64 -lSystem %t/arm64.o -o %t/arm64
-# RUN: llvm-objdump --syms --full-contents %t/arm64 | FileCheck %s
+# RUN: llvm-objdump --syms --full-contents --rebase %t/arm64 | FileCheck %s
 
 # CHECK-LABEL: SYMBOL TABLE:
 # CHECK:       {{0*}}[[#%x, SUB1ADDR:]] l {{.*}} __DATA,__data _sub1
@@ -17,6 +17,9 @@
 # CHECK-NEXT:  [[#SUB2ADDR]] f0ffffff
 # CHECK-NEXT:  [[#SUB3ADDR]] 10000000 00000000
 # CHECK-NEXT:  [[#SUB4ADDR]] f0ffffff ffffffff
+# CHECK:       Rebase table:
+# CHECK-NEXT:  segment  section            address     type
+# CHECK-EMPTY:
 
 .globl _main, _subtrahend_1, _subtrahend_2, _minued1, _minued2